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A Study of Three Galaxy Types, Galaxy Formation, and Warm Dark Matter

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International Journal of Astronomy and Astrophysics 2021年第4期11卷 489-508页

作者： bruce Hoeneisen Universidad San Francisco de Quito Quito Ecuador

We try to bridge the gap between the theory of linear density-velocity-gravitational perturbations in the early universe, and the relaxed galaxies we observe today. We succeed quantitatively for dark matter if dark matter is warm. The density runs of baryons and of dark matter of relaxed galaxies are well described by hydro-static equations. The evolution from initial linear perturbations to final relaxed galaxies is well described by hydro-dynamical equations. These equations necessarily include dark matter velocity dispersion. If the initial perturbation is large enough, the halo becomes self-gravitating. The adiabatic compression of the dark matter core determines the final core density, and provides a negative stabilizing feedback. The relaxed galaxy halo may form adiabatically if dark matter is warm. The galaxy halo radius continues to increase indefinitely, so has an ill-defined mass.

关键词： Galaxy Formation Warm Dark Matter Adiabatic Invariant of Warm Dark Matter

exploring Inflation Options for Warm Dark Matter Coupled to the Higgs Boson

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International Journal of Astronomy and Astrophysics 2023年第3期13卷 217-235页

作者： bruce Hoeneisen Universidad San Francisco de Quito Quito Ecuador

We extend the Standard Model with a scalar warm dark matter field S with an interaction with the Higgs boson ∅. This warm dark matter scenario is in agreement with cosmological observations if S and ∅ come into thermal and diffusive equilibrium before the temperature drops below the Higgs boson mass mH. We study inflation driven by the fields ∅ or S, and also study preheating and reheating, in order to constrain the parameters of this extension of the Standard Model. It is remarkable that, with the current data, these models pass a closure test with no free parameters.

关键词： Warm Dark Matter Inflation Preheating Reheating

Fermion or Boson Dark Matter?

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International Journal of Astronomy and Astrophysics 2020年第3期10卷 203-223页

作者： bruce Hoeneisen Universidad San Francisco de Quito Quito Ecuador

We measure properties of dark matter in four well motivated scenarios: fermions with ultra-relativistic thermal equilibrium (URTe), bosons with URTe, fermions with non-relativistic thermal equilibrium (NRTe), and bosons with NRTe. We attempt to discriminate between these four scenarios with studies of spiral galaxy rotation curves, and galaxy stellar mass distributions. The measurements show evidence for boson dark matter with a significance of 3.5σ, and obtain no significant discrimination between URTe and NRTe.

关键词： Dark Matter Free-Streaming Galaxy Mass Distribution Spiral Galaxy

Cold or Warm Dark Matter?: A Study of Galaxy Stellar Mass Distributions

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International Journal of Astronomy and Astrophysics 2020年第2期10卷 57-70页

作者： bruce Hoeneisen Universidad San Francisco de Quito Quito Ecuador

We compare the observed galaxy stellar mass distributions in the redshift range with expectations of the cold ΛCDM and warm ΛWDM dark matter models, and obtain the warm dark matter cut-off wavenumber: . This result ... 详细信息

We compare the observed galaxy stellar mass distributions in the redshift range edit_***" alt="" />with expectations of the cold ΛCDM and warm ΛWDM dark matter models, and obtain the warm dark matter cut-off wavenumber: edit_***" alt="" />. This result is in agreement with the independent measurements with spiral galaxy rotation curves, confirms that em>kem>fs is due to warm dark matter free-streaming, and is consistent with the scenario of dark matter with no freeze-in and no freeze-out. Detailed properties of warm dark matter can be derived from em>kem>fs. The data disfavors the ΛCDM model.

关键词： Dark Matter Warm Dark Matter Dark Matter Properties Galaxy Stellar Mass

Measurement of the Dark Matter Velocity Dispersion with Galaxy Stellar Masses, UV Luminosities, and Reionization

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International Journal of Astronomy and Astrophysics 2022年第3期12卷 258-272页

作者： bruce Hoeneisen Universidad San Francisco de Quito Quito Ecuador

The root-mean-square of non-relativistic warm dark matter particle velocities scales as vhrms(a)=vhrms(1)/a , where a is the expansion parameter of the universe. This velocity dispersion results in a cut-off of the power spectrum of density fluctuations due to dark matter free-streaming. Let kfs (teq) be the free-streaming comoving cut-off wavenumber at the time of equal densities of radiation and matter. We obtain , and , at 68% confidence, from the observed distributions of galaxy stellar masses and rest frame ultra-violet luminosities. This result is consistent with reionization. From the velocity dispersion cut-off mass we obtain the limits vhrms(1)kfs (teq) >1.5 Mpc-1. These results are in agreement with previous measurements based on spiral galaxy rotation curves, and on the formation of first galaxies and reionization. These measured parameters determine the temperature-to-mass ratio of warm dark matter. This ratio happens to be in agreement with the no freeze-in and no freeze-out warm dark matter scenario of spin 0 dark matter particles decoupling early on from the standard model sector. Spin 1/2 and spin 1 dark matter are disfavored if nature has chosen the no freeze-in and no freeze-out scenario. An extension of the standard model of quarks and leptons, with scalar dark matter that couples to the Higgs boson that is in agreement with all current measurements, is briefly reviewed. Discrepancies with limits on dark matter particle mass that can be found in the literature are addressed.

关键词： Warm Dark Matter Galaxy Stellar Mass Galaxy UV Luminosity Reionization

A Dominant Allele of Arabidopsis Pectin-Binding Wall-Associated Kinase Induces a Stress Response Suppressed by MPK6 but Not MPK3 Mutations

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Molecular Plant 2012年第4期5卷 841-851页

作者： bruce D. Kohorn Susan L. Kohorn Tanya Todorova Gillian Baptiste Kevin Stansky Meghan McCullough Department of Biology Bowdoin College ME 04011 USA

The plant cell wall is composed of a matrix of cellulose fibers, flexible pectin polymers, and an array of as- sorted carbohydrates and proteins. The receptor-like Wall-Associated Kinases （WAKs） of Arabidopsis bind pectin in the wall, and are necessary both for cell expansion during development and for a response to pathogens and wounding. Mitogen Activated Protein Kinases （MPKs） form a major signaling link between cell surface receptors and both transcrip- tional and enzyme regulation in eukaryotes, and Arabidopsis MPK6 and MPK3 indeed have important roles in develop- ment and the response to stress and pathogens. A dominant allele of WAK2 requires kinase activity and activates a stress response that includes an increased ROS accumulation and the up-regulation of numerous genes involved in pathogen resistance, wounding, and cell wall biogenesis. This dominant allele requires a functional pectin binding and kinase domain, indicating that it is engaged in a WAK signaling pathway. A null mutant of the major plasma membrane ROS-producing enzyme complex, rbohd/f does not suppress the WAK2cTAP-induced phenotype. A mpk6, but not a mpk3, null allele is able to suppress the effects of this dominant WAK2 mutation, thus distinguishing MPK3 and MPK6, whose activity previously was thought to be redundant. Pectin activation of gene expression is abated in a wak2-null, but is tempered by the WAK-dominant allele that induces elevated basal stress-related transcript levels. The results suggest a mechanism in which changes to the cell wall can lead to a large change in cellular responses and help to explain how pathogens and wounding can have general effects on growth.

关键词： Wall Associated Kinases MPK3 MPK6 pectin oligogalacturonides.

14 Guides to Becoming a Successful Leader

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技术经济与管理研究 2000年第3期 9-10页

作者： bruce e.Thom,Q.C. 加拿大埃德蒙顿市市长

1995年，笔者曾在这份杂志上发表过一篇文章，内容是关于城市管理者如何越过政府重组这一“丛林”的20条指针。本文将要阐述的是第二道“丛林”——成为一个成功领导者的艰难历程。在跨越这一历程的过程中，以下14条指针也许会对你有所... 详细信息

1995年，笔者曾在这份杂志上发表过一篇文章，内容是关于城市管理者如何越过政府重组这一“丛林”的20条指针。本文将要阐述的是第二道“丛林”——成为一个成功领导者的艰难历程。在跨越这一历程的过程中，以下14条指针也许会对你有所帮助。需要说明的是，没有人能够告诉你走向成功的全部真谛。但是你可以从成功的领导者那里取得通常的经验，也可以了解到一些影响取得成功的禁忌……

关键词：领导者指针政府重组历程丛林管理者经验禁忌城市

Warm Dark Matter and the Formation of First Galaxies

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Journal of Modern Physics 2022年第6期13卷 932-948页

作者： bruce Hoeneisen Universidad San Francisco de Quito Quito Ecuador

By numerical integration of hydro-dynamical equations, we study the formation of elliptical and spiral galaxies starting from primordial linear density-velocity-gravitational perturbations. Both dark matter and baryons are included. Warm dark matter perturbations acquire two low mass cut-offs: the free-streaming cut-off due to the power spectrum free-streaming cut-off factor τ2(k), and the velocity dispersion cut-off. The Press-Schechter mass distribution does not include velocity dispersion, and should not be used below the velocity dispersion cut-off mass. From the formation of first galaxies and reionization, we estimate limits on the non-relativistic warm dark matter velocity dispersion at expansion parameter , with .

关键词： Warm Dark Matter First Galaxies First Stars Population III Stars Reioniza-tion

Active-Sterile Neutrino Oscillations and Leptogenesis

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Journal of Modern Physics 2021年第9期12卷 1248-1266页

作者： bruce Hoeneisen Universidad San Francisco de Quito Quito Ecuador

We study coherent active-sterile neutrino oscillations as a possible source of leptogenesis. To this end, we add 3 gauge invariant Weyl_R neutrinos to the Standard Model with both Dirac and Majorana type mass terms. We find that the measured active neutrino masses and mixings, and successful baryogenesis via leptogenesis, may be achieved with fine-tuning, if at least one of the sterile neutrinos has a mass in the approximate range 0.14 to 1.1 GeV.

关键词： Leptogenesis Majorana Neutrino Matter-Antimatter Asymmetry